Improving *_add and testing more scenarios

Lst_add had a bug when adding to existing lists that was not caught
before because it was being tested indirectly.

Arr_add had a bug on the index counter that was not caught because
it was not used anywhere else but the tests, which were incomplete.

idiom/data.sh

@@ -147,7 +147,7 @@ Lst () {
 Lst_add () {
 	_R=$1
 	shift
-	eval "$_R=\"\${$_R:-}\$*\""
+	eval "$_R=\"\$$_R\${$_R:+\$__EOL__}\$*\""
 }
 
 # The Set pseudotype constructor
@@ -173,19 +173,13 @@ Set_add () {
 Arr () {
 	_A=$((_A + 1))
 	_R=_A$_A
-	eval "$_R=-1"
-	if test $# -gt 0
-	then
-		eval "$_R=-1"
-		Arr_add $_R "$@"
-	else
-		eval "$_R=0"
-	fi
+	eval "$_R=0"
+	test $# -lt 1 || Arr_add $_R "$@"
 }
 
 Arr_add () {
 	_R=$1
-	eval "$_R=$(($_R + $#))"
+	eval "$_R=$(($_R + $# - 1))"
 	while test $# -gt 1
 	do shift ; eval "${_R}i$(($_R - $#))=\$1"
 	done

test/_idiom/003-Lst.sh

@@ -18,3 +18,17 @@ test_Lst_simple () {
 	eval deref=\$$_R
 	tap_assert "foo${__EOL__}bar${__EOL__}baz" "$deref"
 }
+
+test_Lst_add_to_existing () {
+	Lst foo bar baz
+	Lst_add $_R qux
+	eval deref=\$$_R
+	tap_assert "foo${__EOL__}bar${__EOL__}baz${__EOL__}qux" "$deref"
+}
+
+test_Lst_add_to_existing_empty_list () {
+	Lst
+	Lst_add $_R foo bar baz
+	eval deref=\$$_R
+	tap_assert "foo${__EOL__}bar${__EOL__}baz" "$deref"
+}

test/_idiom/004-Set.sh

@@ -36,3 +36,17 @@ test_Set_uniqueness_C () {
 	eval deref=\$$_R
 	tap_assert "bar${__EOL__}foo" "$deref"
 }
+
+test_Set_add_to_existing () {
+	Set foo bar baz
+	Set_add $_R baz foo qux bar qux
+	eval deref=\$$_R
+	tap_assert "foo${__EOL__}bar${__EOL__}baz${__EOL__}qux" "$deref"
+}
+
+test_Set_add_to_existing_empty_list () {
+	Set
+	Set_add $_R foo bar baz
+	eval deref=\$$_R
+	tap_assert "foo${__EOL__}bar${__EOL__}baz" "$deref"
+}

test/_idiom/005-Arr.sh

@@ -11,10 +11,40 @@ test_Arr_unary_zerolength () {
 	Arr ""
 	eval deref=\$$_R
 	tap_assert "1" "$deref"
+	eval deref=\$${_R}i0
+	tap_assert "" "$deref"
 }
 
 test_Arr_simple () {
 	Arr foo bar baz
 	eval deref=\$$_R
 	tap_assert "3" "$deref"
+	eval deref=\$${_R}i0
+	tap_assert "foo" "$deref"
+	eval deref=\$${_R}i1
+	tap_assert "bar" "$deref"
+	eval deref=\$${_R}i2
+	tap_assert "baz" "$deref"
+}
+
+test_Arr_add_to_existing () {
+	Arr foo bar baz
+	Arr_add $_R qux
+	eval deref=\$$_R
+	tap_assert "4" "$deref"
+	eval deref=\$${_R}i3
+	tap_assert "qux" "$deref"
+}
+
+test_Arr_add_to_existing_empty_list () {
+	Arr
+	Arr_add $_R foo bar baz
+	eval deref=\$$_R
+	tap_assert "3" "$deref"
+	eval deref=\$${_R}i0
+	tap_assert "foo" "$deref"
+	eval deref=\$${_R}i1
+	tap_assert "bar" "$deref"
+	eval deref=\$${_R}i2
+	tap_assert "baz" "$deref"
 }